Given the following formulas: The ratio of useful work done by the pulley (mgh) to the work you put in (FAx) is the efficiency of the pulley, which is usually expressed as a percent: Efficiency = useful work out FAX Work in (100%) = mgh (100%) The mechanical advantage of a machine is the ratio of the output force to the input force, or: Mechanical Advantage = F/mg Calculating the average efficiency and the average mechanical advantage in this question. Trial Mass Height Distance Pulled Force Pulled Weight Work by pulley Work by you (kg) (m) (m) (N) (N) ( J ) ( J ) 1 0.44 0.44 5.55 9.81 4.3164 2.442 2 .5 0.46 0.46 3.11 4.905 2.2563 1.4306 3 1.5 0.36 0.36 8.2 14.715 5.2974 2.952